The present invention relates to an equipment specifying system for specifying equipment often used by a user among a plurality of pieces of equipment to which gas is supplied through a single flow path.
In the past, a system has been known, which is capable of distinguishing ignition of a gas unit from gas leakage in accordance with a change in a flow ratand of gas flowing through a flow path. For example, Japanese Laid-Open Publication No. 9-304134 describes this type of system.
FIG. 1 shows a structure of the system described in Japanese Laid-Open Publication No. 9-304134. The system shown in FIG. 1 includes flow rate measuring means 1, flow rate pattern indicator calculation means 2, pattern recognition means 3, and storage means 4.
The flow rate measuring means 1 measures a flow rate of gas flowing through a flow path, and outputs a flow rate measuring signal representing the measured flow rate to the flow rate pattern indicator calculation means 2. The flow rate pattern indicator calculation means 2 creates a flow rate pattern indicator of gas flowing through the flow path, based on the flow rate measuring signal. The storage means 4 previously stores a plurality of basic flow rate pattern indicators. The pattern recognition means 3 compares the flow rate pattern indicator created by the flow rate pattern indicator calculation means 2 with a plurality of flow rate pattern indicators previously stored in the storage means 4, thereby determining whether a change in a flow rate of gas flowing through the flow path is based on ignition of a gas unit or gas leakage.
The above-mentioned conventional system is predicated upon measurement of a flow rate of gas flowing through a flow path. Measurement of a flow rate of gas generally requires some calculation processing with respect to a signal output from a sensor. In the case where a flow rate of gas is changed at high speed (e.g., in the case where a gas flow is in a transient state), the number of data to be sampled is not sufficient, so that measurement of a flow rate of gas does not follow a high-speed change in a flow rate of gas.
An equipment specifying system of the present invention, includes: a flow path for supplying gas to a plurality of pieces of equipment, an ultrasonic propagation signal measuring section for measuring a propagation signal based on a time during which an ultrasonic wave propagates across the flow path: a signal pattern generation section for generating a signal pattern based on a change in the propagation signal; a signal pattern storage section for previously storing a plurality of signal patterns respectively corresponding to the plurality of pieces of equipment; a signal pattern comparison section for comparing the signal pattern generated by the signal pattern generation section with the plurality of signal patterns previously stored in the signal pattern storage section; and an equipment specifying section for specifying currently used equipment among the plurality of pieces of equipment, in accordance with the comparison results obtained by the signal pattern comparison section.
In one embodiment of the present invention, the equipment specifying system further includes a use time limit setting section for setting a use time limit to the specified equipment.
In another embodiment of the present invention, the equipment specifying system further includes an equipment use time storage section for storing a use time of the specified equipment.
In another embodiment of the present invention, the ultrasonic propagation signal measuring section includes a first ultrasonic transducer and a second ultrasonic transducer, and the propagation signal represents a difference (T2xe2x88x92T1) between a propagation time T1 during which an ultrasonic wave propagates from the first ultrasonic transducer to the second ultrasonic transducer across the flow path and a propagation time T2 during which an ultrasonic wave propagates from the second ultrasonic transducer to the first ultrasonic transducer across the flow path.
In another embodiment of the present invention, the ultrasonic propagation signal measuring section includes a first ultrasonic transducer and a second ultrasonic transducer, and the propagation signal represents one of a propagation time T1 during which an ultrasonic wave propagates from the first ultrasonic transducer to the second ultrasonic transducer across the flow path and a propagation time T2 during which an ultrasonic wave propagates from the second ultrasonic transducer to the first ultrasonic transducer across the flow path.
In another embodiment of the present invention, the ultrasonic propagation signal measuring section is controlled so that a frequency of measuring the propagation signal is increased, in response to a detection of a change in the propagation signal.
In another embodiment of the present invention, in a case where the signal pattern generated by the signal pattern generation section does not match with any of the plurality of signal patterns stored in the signal pattern storage section, the signal pattern comparison section requests a user to store the signal pattern generated by the signal pattern generation section in the signal pattern storage section
In another embodiment of the present invention, in a case where the signal pattern generated by the signal pattern generation section does not match with any of the plurality of signal patterns stored in the signal pattern storage section, the signal pattern comparison section automatically stores the signal pattern generated by the signal pattern generation section in the signal pattern storage section.
In another-embodiment of the present invention, in a case where the signal pattern generated by the signal pattern generation section does not match with any of the plurality of signal patterns stored in the signal pattern storage section, the signal pattern comparison section conducts a gas leakage check.
Thus, the invention described herein makes possible the advantage of providing an equipment specifying system which is capable of specifying currently used equipment, by utilizing a propagation signal based on a time during which an ultrasonic wave propagates across a flow path, without utilizing a flow rate measuring signal.